Osisko Windfall Drilling Intercepts Wide High-Grade in Expansion Holes

163 g/t Au over 8.8 metres in Lynx 4

32.4 g/t Au over 5.7 metres in Triple Lynx

TORONTO, Dec. 08, 2023 (GLOBE NEWSWIRE) — Osisko Mining Inc. (OSK:TSX. “Osisko” or the “Corporation”) is pleased to provide new analytical results from the ongoing drill program at its 100% owned Windfall gold project located in the Abitibi greenstone belt, Urban Township, Eeyou Istchee James Bay, Québec.

Significant new analytical results presented below include 97 intercepts in 31 drill holes (12 from surface, 19 from underground) and 22 wedges. The infill intercepts are located inside defined February 2023 mineral resource estimate (“MRE”) blocks (see Osisko news release dated February 17, 2021). The expansion intercepts are located outside the February 2023 MRE blocks and either expand resource wireframes or are in a defined zone or corridor but do not yet correlate to a specific wireframe.

Osisko Chief Executive Officer John Burzynski commented: “Today’s results underscore once again how much room there is to grow at Windfall with the headline holes located outside the resource released in February earlier this year. Targeted infill drilling also returned high-grade intercepts highlighting the robust grade of the deposit.”

Selected high-grade intercepts include: 163 g/t Au over 8.8 metres in OSK-W-21-1462-W11; 178 g/t Au over 2.9 metres in OSK-W-21-2551-W5; 135 g/t Au over 2.0 metres in OSK-W-21-1871-W1; 104 g/t Au over 2.4 metres in OSK-W-21-1949-W6; 95.2 g/t Au over 2.1 metres in OSK-W-21-2287-W7; 32.4 g/t Au over 5.7 metres in OSK-W-21-2540-W5, 49.4 g/t Au over 2.0 metres in WST-21-0903, 35.7 g/t Au over 2.4 metres in WST-21-0901, 21.5 g/t Au over 4.0 metres in OSK-W-21-2544-W2 and 42.7 g/t Au over 2.0 metres in WST-21-0879. Maps showing hole locations and full analytical results are available at www.osiskomining.com.

Infill Drilling

Hole No. From (m) To (m) Interval (m) Au (g/t) uncut Au (g/t) cut to 100 g/t Zone Corridor
OSK-W-21-1871-W1 888.6 891.0 2.4 12.5   UDD_4106 Underdog
  1008.0 1010.0 2.0 135 50.1 UDD_4501 Underdog
including 1008.0 1009.0 1.0 270 100
OSK-W-21-1871-W3 491.0 493.1 2.1 7.90   CA2_2211 Caribou
including 491.5 491.9 0.4 18.8  
  549.0 551.0 2.0 5.32   CA2_2233 Caribou
OSK-W-21-1949-W6 747.2 749.6 2.4 104 27.6 LXM_3345 Lynx
including 748.1 748.6 0.5 466 100
OSK-W-21-2287-W7 1213.9 1216.0 2.1 95.2   LX4_3449 Lynx 4
OSK-W-21-2407-W2 802.0 805.0 3.0 8.55   UDD_4106 Underdog
including 802.8 803.5 0.7 21.1  
OSK-W-21-2416-W7 1018.0 1020.0 2.0 41.3 15.8 TLX_3162 Triple Lynx
including 1019.3 1019.6 0.3 270 100
  1032.0 1034.0 2.0 36.8 23.9 TLX_3162 Triple Lynx
including 1032.9 1033.2 0.3 186 100
OSK-W-21-2512-W2 433.0 435.0 2.0 7.24   CA2_2211 Caribou
  687.6 690.0 2.4 28.2   UDD_4100 Underdog
including 688.3 689.3 1.0 65.8  
  694.0 696.0 2.0 6.01   UDD_4100 Underdog
  715.0 720.0 5.0 5.04   UDD_4102 Underdog
  724.0 726.0 2.0 4.28   UDD_4102 Underdog
OSK-W-21-2531-W3 810.0 813.0 3.0 11.4   UDD_4110 Underdog
  873.0 877.0 4.0 10.3   UDD_4101 Underdog
  913.0 916.4 3.4 10.2   UDD_4100 Underdog
OSK-W-21-2531-W4 845.3 847.3 2.0 6.79   UDD_4101 Underdog
including 845.3 845.6 0.3 35.3  
OSK-W-21-2532-W3 828.0 833.0 5.0 8.29   UDD_4100 Underdog
including 832.0 833.0 1.0 24.0  
  837.8 842.0 4.2 19.0 16.1 UDD_4100 Underdog
including 840.0 840.4 0.4 131 100
OSK-W-21-2537-W3 938.0 940.0 2.0 12.6   TLX_3183 Triple Lynx
OSK-W-21-2544-W2 774.9 777.0 2.1 4.22   TLX_3171 Triple Lynx
  783.0 787.0 4.0 21.5   TLX_3171 Triple Lynx
including 784.5 785.2 0.7 62.8  
  793.0 795.0 2.0 19.0   TLX_3184 Triple Lynx
including 794.0 794.4 0.4 93.3  
  989.0 991.0 2.0 17.5   TLX_3195 Triple Lynx
including 989.4 990.0 0.6 58.1  
OSK-W-21-2551-W5 941.3 943.5 2.2 17.3   LX4_3430 Lynx 4
including 942.0 942.4 0.4 78.6  
  958.4 961.3 2.9 178 36.3 LX4_3430 Lynx 4
including 958.8 959.7 0.9 556 100
OSK-W-21-2578-W3 604.7 606.9 2.2 7.71   UDD_4100 Underdog
including 606.1 606.9 0.8 20.9  
OSK-W-21-2587-W1 1030.0 1032.0 2.0 20.5   TLX_3163 Triple Lynx
  1038.0 1040.0 2.0 5.36   TLX_3164 Triple Lynx
including 1038.7 1039.0 0.3 27.1  
  1046.0 1049.0 3.0 3.99   TLX_3164 Triple Lynx
  1089.0 1091.0 2.0 5.66   TLX_3162 Triple Lynx
including 1089.0 1089.4 0.4 16.6  
  1105.6 1109.0 3.4 8.17   TLX_3170 Triple Lynx
OSK-W-21-2600 475.8 478.0 2.2 5.70   Z27_1115 Zone 27
OSK-W-21-2605 1312.0 1314.0 2.0 5.62   LX4_3445 Lynx 4
OSK-W-21-2612-W1 382.6 384.9 2.3 4.02   Z27_1115 Zone 27
including 382.6 383.0 0.4 14.4  
OSK-W-21-2613 916.2 922.0 5.8 14.6   TLX_3161 Triple Lynx
including 916.2 916.6 0.4 38.1  
and 918.7 919.3 0.6 41.0  
  967.9 970.0 2.1 19.8   TLX_3163 Triple Lynx
including 967.9 968.3 0.4 60.9  
and 968.9 969.3 0.4 42.5  
  994.0 996.0 2.0 3.77   TLX_3164 Triple Lynx
including 994.4 995.0 0.6 8.21  
OSK-W-21-2621 628.0 630.0 2.0 18.6   UDD_4101 Underdog
OSK-W-21-2625 814.9 817.3 2.4 10.9   LX4_3437 Lynx 4
including 814.9 815.2 0.3 55.1  
OSK-W-21-2631 133.0 135.0 2.0 26.5   F11_6001 F-11
OSK-W-21-2632 103.0 105.0 2.0 3.66   F11_6000 F-11
  139.0 141.5 2.5 19.6   F11_6009 F-11
including 139.6 140.5 0.9 47.7  
OSK-W-21-2635 568.0 570.4 2.4 4.21   CA2_2211 Caribou
including 570.1 570.4 0.3 24.2  
OSK-W-21-2636 365.0 367.0 2.0 4.26   CA1_2551 Caribou
including 366.0 366.4 0.4 12.4  
  550.0 552.0 2.0 13.0   Z27_1107 Zone 27
including 551.0 551.7 0.7 35.6  
OSK-W-21-2641 118.4 124.0 5.6 4.04   F11_6001 F-11
WST-21-0649 456.0 458.0 2.0 6.23   TLX_3165 Triple Lynx
WST-21-0875 510.0 512.7 2.7 20.7 18.8 LX4_3450 Lynx 4
including 512.2 512.7 0.5 111 100
WST-21-0878 346.0 348.3 2.3 7.43   TLX_3131 Triple Lynx
including 348.0 348.3 0.3 37.7  
WST-21-0879 510.0 512.0 2.0 42.7 25.8 LX4_3450 Lynx 4
including 510.5 511.0 0.5 168 100
  612.5 615.0 2.5 24.0   LX4_3429 Lynx 4
including 612.5 613.0 0.5 78.8  
WST-21-0900 272.9 275.4 2.5 5.33   LHW_3215 Lynx HW
including 275.0 275.4 0.4 22.2  
WST-21-0901 308.0 310.4 2.4 35.7 24.5 LHW_3215 Lynx HW
including 309.6 309.9 0.3 189 100
WST-21-0907 509.5 512.5 3.0 19.8   LX4_3430 Lynx 4
including 509.5 511.0 1.5 39.5  
  644.0 646.1 2.1 38.8 35.1 LX4_3448 Lynx 4
including 645.0 645.5 0.5 116 100
WST-21-0912 603.0 605.1 2.1 38.6   LX4_3429 Lynx 4
including 603.6 604.5 0.9 74.9  
WST-21-0920B 301.1 303.2 2.1 4.08   LHW_3215 Lynx HW
WST-21-0922 102.0 104.0 2.0 3.57   LXM_3304 Lynx

Notes: True widths are estimated at 55 – 80% of the reported core length interval. See “Quality Control and Reporting Protocols” below. CA1 and CA2 = Caribou, LX4 = Lynx 4, LHW = Lynx Hanging Wall, LXM = Lynx Main, TLX = Triple Lynx, UDD = Underdog, F11 = F-Zones, Z27 = Zone 27.

Expansion Drilling

Hole No. From (m) To (m) Interval (m) Au (g/t) uncut Au (g/t) cut to 100 g/t Zone Corridor
OSK-W-21-1432-W11 929.3 938.1 8.8 163 26.0 LX4 Lynx
including 929.3 931.0 1.7 811 100
OSK-W-21-1871-W2 754.0 756.0 2.0 4.06   UDD Underdog
OSK-W-21-2287-W7 1233.0 1235.0 2.0 24.2   LX4 Lynx 4
including 1233.5 1234.4 0.9 49.0  
OSK-W-21-2407-W2 769.3 771.9 2.6 13.4   UDD Underdog
including 769.3 769.7 0.4 57.1  
OSK-W-21-2465-W4 765.6 767.7 2.1 23.0   TLX Triple Lynx
including 766.8 767.7 0.9 50.2  
OSK-W-21-2465-W6 938.0 940.0 2.0 4.61   TLX Triple Lynx
OSK-W-21-2540-W5 948.0 953.7 5.7 32.4 26.1 TLX Triple Lynx
including 951.7 952.7 1.0 136 100
OSK-W-21-2540-W6 949.0 951.0 2.0 11.8   TLX Triple Lynx
including 949.0 950.0 1.0 23.3  
  955.0 957.0 2.0 29.0   TLX Triple Lynx
including 955.6 956.4 0.8 71.1  
OSK-W-21-2544-W2 819.0 821.0 2.0 5.18   TLX Triple Lynx
including 819.9 820.2 0.3 29.7  
OSK-W-21-2578-W3 589.5 591.6 2.1 7.42   UDD Underdog
including 590.1 590.7 0.6 24.7  
OSK-W-21-2587-W1 967.0 969.0 2.0 4.01   TLX Triple Lynx
including 967.0 967.9 0.9 8.06  
OSK-W-21-2589 131.6 133.6 2.0 7.71   LNX Lynx
including 132.8 133.2 0.4 31.0  
OSK-W-21-2599 725.0 727.0 2.0 24.7   CA2 Caribou
including 725.0 726.0 1.0 49.3  
  730.0 732.0 2.0 5.92   CA2 Caribou
  745.4 748.3 2.9 5.42   CA2_2220 Caribou
OSK-W-21-2613 1015.0 1017.0 2.0 5.65   TLX Triple Lynx
OSK-W-21-2635 597.3 600.0 2.7 12.0   CA2 Caribou
including 598.1 598.4 0.3 40.4  
WST-21-0649 606.0 608.0 2.0 5.94   LX4 Lynx
including 606.4 606.7 0.3 37.2  
WST-21-0793 74.0 76.0 2.0 3.72   LNX Lynx
including 74.3 75.1 0.8 8.11  
WST-21-0863 336.3 338.7 2.4 6.80   TLX Triple Lynx
including 338.3 338.7 0.4 29.1  
WST-21-0878 138.0 140.5 2.5 3.93   TLX Triple Lynx
WST-21-0886 231.0 233.0 2.0 8.62   LSW Lynx SW
including 232.6 233.0 0.4 42.8  
  319.2 323.8 4.6 6.98   LSW Lynx SW
including 319.2 319.5 0.3 35.7  
and 320.1 320.4 0.3 30.9  
  362.4 364.4 2.0 4.74   LSW_3502 Lynx SW
including 362.4 362.7 0.3 31.0  
WST-21-0894B 101.0 103.0 2.0 4.94   BCT Bobcat
including 101.3 101.8 0.5 19.0  
WST-21-0898 239.5 241.8 2.3 10.3   TLX Triple Lynx
including 240.7 241.4 0.7 31.4  
WST-21-0903 274.1 276.1 2.0 49.4   TLX Triple Lynx
WST-21-0907 567.0 569.0 2.0 7.94   LX4 Lynx
including 567.0 567.8 0.8 19.5  
  583.0 585.0 2.0 3.53   LX4 Lynx 4
including 583.5 584.0 0.5 13.5  
WST-21-0909 366.4 368.5 2.1 3.88   TLX Triple Lynx
including 367.8 368.1 0.3 11.3  
  384.0 386.4 2.4 5.94   TLX Triple Lynx
including 385.1 385.5 0.4 32.1  
  409.0 411.5 2.5 4.92   TLX Triple Lynx
including 411.1 411.5 0.4 15.3  
WST-21-0915B 247.0 249.5 2.5 9.56   TLX Triple Lynx
including 247.0 247.5 0.5 45.0  
  358.6 361.2 2.6 22.2   TLX Triple Lynx
including 359.6 360.3 0.7 63.7  
  368.2 370.5 2.3 4.01   TLX Triple Lynx
WST-21-0916A 386.0 388.0 2.0 4.68   TLX Triple Lynx
including 387.2 387.5 0.3 10.6  

Notes: True widths are estimated at 55 – 80% of the reported core length interval. See “Quality Control and Reporting Protocols” below. BCT = Bobcat, CA2 = Caribou, LNX= Lynx, LSW = Lynx South West, LX4 = Lynx 4, TLX = Triple Lynx, UDD = Underdog.

Drill hole location

Hole Number Azimuth (°) Dip (°) Length (m) UTM E UTM N Elevation Section
OSK-W-21-1432-W11 132 -55 1149 453811 5435779 400 4300
OSK-W-21-1871-W1 331 -56 1119 452496 5434397 402 2475
OSK-W-21-1871-W2 331 -56 915 452496 5434397 402 2475
OSK-W-21-1871-W3 331 -56 906 452496 5434397 402 2475
OSK-W-21-1949-W6 105 -57 1227 453440 5435479 401 3825
OSK-W-21-2287-W7 116 -53 1320 453607 5435714 404 4075
OSK-W-21-2407-W2 347 -55 843 452315 5434420 399 2325
OSK-W-21-2416-W7 123 -54 1104 453169 5435624 412 3650
OSK-W-21-2465-W4 123 -61 1053 453398 5435556 413 3825
OSK-W-21-2465-W6 123 -61 993 453398 5435556 413 3825
OSK-W-21-2512-W2 331 -54 834 452448 5434465 400 2475
OSK-W-21-2531-W3 344 -62 1329 452566 5434415 403 2550
OSK-W-21-2531-W4 344 -62 1203 452566 5434415 403 2550
OSK-W-21-2532-W3 341 -60 1191 452478 5434430 401 2475
OSK-W-21-2537-W3 114 -54 1024 452981 5435549 420 3450
OSK-W-21-2540-W5 117 -60 1311 453465 5435640 410 3925
OSK-W-21-2540-W6 117 -60 1541 453465 5435640 410 3925
OSK-W-21-2544-W2 128 -50 1044 452960 5435539 419 3425
OSK-W-21-2551-W5 120 -55 1023 453622 5435635 405 4050
OSK-W-21-2578-W3 350 -53 723 452178 5434397 399 2200
OSK-W-21-2587-W1 127 -59 1176 453350 5435673 418 3850
OSK-W-21-2589 130 -49 663 452960 5435539 420 3425
OSK-W-21-2599 328 -62 774 452787 5434526 397 2800
OSK-W-21-2600 329 -50 789 452470 5434626 403 2550
OSK-W-21-2605 112 -55 1401 453552 5435669 408 4025
OSK-W-21-2612-W1 333 -51 690 452391 5434638 402 2500
OSK-W-21-2613 114 -53 1092 452981 5435549 420 3450
OSK-W-21-2621 344 -53 1001 452272 5434396 399 2275
OSK-W-21-2625 33 -77 891 454135 5435058 396 4225
OSK-W-21-2631 158 -47 165 452336 5435850 406 3050
OSK-W-21-2632 141 -44 153 452363 5435857 406 3075
OSK-W-21-2635 327 -56 708 452684 5434475 402 2675
OSK-W-21-2636 337 -52 801 452499 5434619 403 2575
OSK-W-21-2641 177 -46 165 452436 5435884 407 3150
WST-21-0649 136 -47 790 453258 5435211 98 3525
WST-21-0793 125 -15 121 453463 5435327 32 3775
WST-21-0863 135 -64 403 453508 5435327 -7 3800
WST-21-0875 144 -47 577 453322 5435235 54 3600
WST-21-0878 128 -40 711 453375 5435297 -26 3675
WST-21-0879 139 -44 724 453258 5435209 96 3525
WST-21-0886 128 -51 375 452954 5435004 253 3175
WST-21-0894B 132 -52 417 452955 5435004 253 3175
WST-21-0898 141 -61 402 453508 5435327 -7 3800
WST-21-0900 122 -13 316 453462 5435326 33 3775
WST-21-0901 116 -18 340 453462 5435327 32 3775
WST-21-0903 120 -61 322 453509 5435328 -7 3800
WST-21-0907 130 -40 701 453374 5435296 -26 3675
WST-21-0909 151 -59 426 453507 5435328 -7 3800
WST-21-0912 141 -41 640 453258 5435209 96 3525
WST-21-0915B 143 -63 490 453507 5435328 -7 3800
WST-21-0916A 146 -52 586 453321 5435235 54 3600
WST-21-0920B 135 -24 348 453462 5435326 32 3775
WST-21-0922 146 -35 114 453314 5435164 124 3550

Bobcat
Mineralization most commonly occurs in gold-bearing quartz-pyrite veins controlled by northeast trending faults and shears and to a lesser extent in minor crustiform quartz-tourmaline-ankerite-pyrite veins and pyrite replacement zones and stockwork. Mineralization is hosted in sheared mafic volcanics, rhyolites near faults, or at the contact with felsic porphyritic intrusions.

Caribou Zone
Mineralization most commonly occurs in gold-bearing pyrite stockworks as well as semi-massive pyrite replacement zones associated with phyllic alteration (sericite-pyrite ± silica) with sulphides, pyrite dominated with minor chalcopyrite and sphalerite ranging from trace to up to 20%, and local visible gold. Mineralization is hosted in rhyolites or mafic-intermediate volcanics frequently at or near faults or the contact with felsic porphyritic intrusions.

F-Zones
Mineralization is hosted in sheared andesites with carbonate replacement or quartz veining and occurs as quartz ± ankerite veinlets or as replacement type in shear zones and is characterised by trace to 10% pyrite with local visible gold. Alteration is dominated by sericite-fuchsite-tourmaline-pyrite.

Lynx Zone
Mineralization occurs as grey to translucent quartz-carbonate-pyrite-tourmaline veins and pyrite replacement zones and stockworks. Vein-type mineralization is associated with haloes of pervasive sericite-pyrite ± silica alteration and contain sulphides (predominantly pyrite with minor amounts of chalcopyrite, sphalerite, galena, arsenopyrite, and pyrrhotite) and local visible gold. Replacement mineralization is associated with strong pervasive silica-sericite-ankerite ± tourmaline alteration and contains disseminated pyrite from trace to 80% with local visible gold. Pyrite stockworks can form envelopes that reach several tens of metres thick. Fuchsite alteration is common and is spatially constrained to near the gabbros. Mineralization occurs at or near geological contacts between felsic porphyritic or fragmental intrusions and the host rhyolites or gabbros and locally can be hosted along the gabbro-rhyolite contact.

Underdog
Mineralization most commonly occurs in gold-bearing quartz-pyrite (± tourmaline) veins and as disseminated, stringer, semi-massive to massive pyrite with minor sphalerite, chalcopyrite and molybdenite associated with strong sericite and silica alteration. Mineralization is hosted along the intrusive contacts of a three-phase composite felsic porphyritic unit which cross-cuts felsic and mafic volcanic sequences.

Zone 27
Mineralization most commonly occurs as replacement-type characterized by 5% to 50% disseminated, stringer, semi-massive or stockwork pyrite, ptygmatic tourmaline veins, quartz-tourmaline crustiform veins, local quartz-carbonate veins, and local visible gold. Mineralization is associated with moderate to strong sericite, weak to strong silica, weak chlorite and carbonate and locally weak fuchsite and is hosted in strongly altered andesites, in or at the contact of the rhyolite, or along the contacts with felsic porphyritic intrusions.

Qualified Person
The scientific and technical content of this news release has been reviewed, prepared and approved by Mr. Louis Grenier, M.Sc.A., P.Geo. (OGQ 800), Director of Exploration for Osisko’s Windfall gold project, who is a “qualified person” as defined by National Instrument 43-101 – Standards of Disclosure for Mineral Projects (“NI 43-101”).

Quality Control and Reporting Protocols
True width determination is estimated at 55-80% of the reported core length interval for the zone. Assays are uncut except where indicated. Intercepts occur within geological confines of major zones but have not been correlated to individual vein domains at this time. Reported intervals include minimum weighted averages of 3.5 g/t Au diluted over core lengths of at least 2.0 metres. NQ core assays were obtained by either 1-kilogram screen fire assay or standard 50-gram fire-assaying-AA finish or gravimetric finish at (i) ALS Laboratories in Val d’Or, Québec, Vancouver, British Colombia, Lima, Peru or Vientiane, Laos (ii) Bureau Veritas in Timmins, Ontario. The 1-kilogram screen assay method is selected by the geologist when samples contain coarse gold or present a higher percentage of pyrite than surrounding intervals. Selected samples are also analyzed for multi-elements, including silver, using a Four Acid Digestion-ICP-MS method at ALS Laboratories. Drill program design, Quality Assurance/Quality Control (“QA/QC”) and interpretation of results is performed by qualified persons employing a QA/QC program consistent with NI 43-101 and industry best practices. Standards and blanks are included with every 20 samples for QA/QC purposes by the Corporation as well as the lab. Approximately 5% of sample pulps are sent to secondary laboratories for check assay.

About the Windfall Gold Deposit
The Windfall gold deposit is located between Val-d’Or and Chibougamau in the Abitibi region of Québec, Canada. The Mineral Resource Estimate (MRE) defined by Osisko, as disclosed in the news release dated February 17, 2023 is supported by the technical report entitled “Preliminary Economic Assessment Update for the Windfall Project” dated April 26, 2023 (that includes Windfall Mineral Resource Estimate with an effective date  of November 30, 2020), and assuming a cut-off grade of 3.50 g/t Au, comprises 521,000 tonnes at 11.3 g/t Au (189,000 ounces) in the measured mineral resource category, 5,502,000 tonnes at 9.4 g/t Au (1,668,000 ounces) in the indicated mineral resource category and 16,401,000 tonnes at 8.0 g/t Au (4,244,000 ounces) in the inferred mineral resource category. The key assumptions, parameters and methods used to estimate the mineral resource estimate disclosed in the February 17, 2023 news release are further described in the full technical report prepared by BBA Inc. in accordance with NI 43-101 and is available on SEDAR (www.sedar.com) under the Corporation’s issuer profile. The Windfall gold deposit is currently one of the highest-grade resource-stage gold projects in Canada and has world-class scale. Mineralization occurs in three principal zones: Lynx, Main Zone, and Underdog. Mineralization is generally comprised of sub-vertical zones following intrusive porphyry contacts plunging to the northeast. The resources are defined from surface to a depth of 1,600 metres as it now includes the Triple 8 (T8) zone. The resources excluding T8 are defined from surface to a depth of 1,200 metres. The deposit remains open along strike and at depth. Mineralization has been identified at surface in some areas and as deep as 2,625 metres in others with significant potential to extend mineralization down-plunge and at depth.

About Osisko Mining Inc.
Osisko is a mineral exploration company focused on the acquisition, exploration, and development of gold resource properties in Canada. Osisko holds a 100% interest in the high-grade Windfall gold deposit located between Val-d’Or and Chibougamau in Québec and holds a 100% undivided interest in a large area of claims in the surrounding Urban Barry area and nearby Quévillon area (over 2,600 square kilometres).

Cautionary Note Regarding Forward-Looking Information
This news release contains “forward-looking information” within the meaning of the applicable Canadian securities legislation that is based on expectations, estimates, projections and interpretations as at the date of this news release. Any statement that involves predictions, expectations, interpretations, beliefs, plans, projections, objectives, assumptions, future events or performance (often, but not always, using phrases such as “expects”, or “does not expect”, “is expected”, “interpreted”, “management’s view”, “anticipates” or “does not anticipate”, “plans”, “budget”, “scheduled”, “forecasts”, “estimates”, “potential”, “feasibility”, “believes” or “intends” or variations of such words and phrases or stating that certain actions, events or results “may” or “could”, “would”, “might” or “will” be taken to occur or be achieved) are not statements of historical fact and may be forward-looking information and are intended to identify forward-looking information. This news release contains the forward-looking information pertaining to, among other things: the Windfall gold deposit being one of the highest-grade resource-stage gold projects in Canada and having world-class scale; the key assumptions, parameters and methods used to estimate the mineral resource estimate disclosed in this news release; the prospects, if any, of the Windfall gold deposit; timing and ability of Osisko to file a technical report for the mineral resource estimate disclosed in this news release; the timing and ability of Osisko, if at all, to publish a feasibility study for the Windfall gold deposit; the amount and type of drilling to be completed and the timing to complete such drilling; the focus of the remaining infill drilling; the trend of grade increase; the Lynx zone remaining open to expansion down plunge; upgrading a inferred mineral resource to a measured mineral resource or indicated mineral resource category; future drilling at the Windfall gold deposit; the significance of historic exploration activities and results. Such factors include, among others, risks relating to the ability of exploration activities (including drill results) to accurately predict mineralization; errors in management’s geological modelling; the ability of Osisko to complete further exploration activities, including (infill) drilling; property and royalty interests in the Windfall gold deposit; the ability of the Corporation to obtain required approvals; the results of exploration activities; risks relating to mining activities; the global economic climate; metal prices; dilution; environmental risks; and community and non-governmental actions. Although the forward-looking information contained in this news release is based upon what management believes, or believed at the time, to be reasonable assumptions, Osisko cannot assure shareholders and prospective purchasers of securities of the Corporation that actual results will be consistent with such forward-looking information, as there may be other factors that cause results not to be as anticipated, estimated or intended, and neither Osisko nor any other person assumes responsibility for the accuracy and completeness of any such forward-looking information. Osisko does not undertake, and assumes no obligation, to update or revise any such forward-looking statements or forward-looking information contained herein to reflect new events or circumstances, except as may be required by law.

CONTACT INFORMATION:
John Burzynski
Chief Executive Officer
Telephone (416) 363-8653

Osisko Mining Inc